Avengeance

iTrader: (4)

Just got my 4L80e all the way wired and bolted in... went to install my PST driveline and ran into a problem.

Ive read all over that the stock M6 driveline length, which is what I had with this PST and had no problems, was the same length as the 4L60 and 4L80 driveline for the F-body.

If thats the case how do I explain this.... keep in mind this is a Spicer slip yoke which may need to be swapped out, I knew there was a chance this yoke might not work. However.... look at the placement of the U joint vs the end of the tail shaft housing... doesnt it seem excessive? Even if I get the right yoke dont I want the placement of the U joint up closer to the tailshaft? Oh yeah.. these pics are taken with the suspension fully loaded.

*I scratched a line in the yoke end so you can see how much actually goes into the tail housing when its installed.*








These photos are with the U joint out of the differential yoke and pulled back to see how far it actually sits into the tail housing, see the scratch I made in the yoke.

Avengeance

iTrader: (4)

FWIW Im running a Moser 9".

If I need a longer shaft... should I compromise the strength of the PST and have it lengthened or get a whole new driveshaft?

Firechikn

iTrader: (15)

Hmm. That's strange. I have the same set up and mine is working o.k. I also bought a spicer yoke. I actually had to cut off about 1/2" so it wouldn't bottom out.

cablebandit

iTrader: (37)

looks too short to me.

slow67

iTrader: (2)

Theres your problem right there......

You can use the stock length driveshaft IF you are running a stock length driveshaft BEFORE the 4L80E swap.

Avengeance

iTrader: (4)

Thanks... looks like Ill have a barely used PST driveshaft for sale.

Firechikn

iTrader: (15)

Oh, you just put the 9" in? Yeah, you have to get a longer shaft. I was thinking you were running the 9" and shaft together already. If your rear is all the way back in the fenders, you may be able to shift the rear forward if the lowers and t/a are adjustable. Get you by until you get the new shaft.

Jays_SSZ28

iTrader: (2)

Thats why I always say measure, don't ask.

Avengeance

iTrader: (4)

I have been running the PST with the 9" though. I previously had a M6, now swapped to a 4L80. Worked fine before. Im still confused. The rear is set up just fine with the TA and adj. lowers.

Oh well.. I just measured everything up and going to order a custom Dennys nitrous ready. Hopefully they have a quick turn around, I havent drove my SS in over 3 months now.

slow67

iTrader: (2)

The T56 and the 4L80 are only about 1/16" difference in length. Looks like you have been running too short of a shaft for a while. FYI I ran my stock driveshaft (and 10 bolt) with both a T56 and a 4L80 (with a yoke change of course).

Avengeance

iTrader: (4)

Thanks for the info....

Thats great, I originally ordered my PST from EPP.... I know for a fact I specified with a Moser 9" when I ordered. I did originally have some vibration issues with the first DS and it was exchanged later on after a U joint went out.... still had the vibration but seemed to hold up.

Damn...

Just got off the phone with Dennys... should be here in 2 weeks.

Bersaglieri

iTrader: (13)

Measure the length, maybe I'll take it off your hands.

I had to get a new D/S made when I went from the 4L60e to the 4L80e. But I told the shop I was going to a 9" soon, so they put in larger U-joints that would work in both. Well when I put the 9" in, I didnt need to change anything. Although I am using a "classic" Iron 9" center section, so perhaps thats the difference.

-Dustin-

forcd ind

iTrader: (7)

ch the amount of yoke showing with the rear loose and with weight on it, see how much diff there is before ordering a new shaft